Low metal loaded, alumina supported, catalyst compositions and amination process

ABSTRACT

The present invention provides catalyst compositions useful for transamination reactions. The catalyst compositions have a catalyst support that includes transitional alumina, use a low metal loading (for example, less than 25 wt. %), and do not require the presence of rhenium. The catalyst compositions are able to advantageously promote transamination of a reactant product (such as the transamination of EDA to DETA) with excellent activity and selectivity, and similar to transaminations promoted using a precious metal-containing catalyst.

CROSS REFERENCE TO RELATED APPLICATION

The present non-provisional patent application is a divisional of U.S.patent application Ser. No. 12/587,355, filed on Oct. 6, 2009, whichapplication claims priority under 35 USC 119(e) from U.S. ProvisionalPatent Application having Ser. No. 61/195,434, filed on Oct. 6, 2008, byKing et al. and entitled LOW METAL LOADED, ALUMINA SUPPORTED, CATALYSTCOMPOSITIONS AND AMINATION PROCESS; both of which are fully incorporatedherein by reference.

FIELD OF THE INVENTION

The invention relates to metal-containing catalyst compositions. Moreparticularly, the invention relates to catalysts that include cobalt,nickel, or copper, or a mixture thereof, with low total metal loadingson an acidic mixed metal oxide support. The invention also relates toamination reactions using the metal-containing catalyst compositions.

BACKGROUND OF THE INVENTION

Linear ethyleneamines are known for their many uses in industry. Forexample, ethylenediamine (EDA) (1,2-diaminoethane) is a strongly basicamine in the form of a colorless liquid having an ammonia-like odor. EDAis a widely used building block in chemical synthesis, withapproximately 500,000,000 kg being produced in 1998. EDA is used inlarge quantities for production of many industrial chemicals, such asbleach activators, fungicides, chelating agents, plastic lubricants,textile resins, polyamide resins, and fuel additives. Diethylenetriamine(DETA) can be used primarily as an intermediate to manufacturewet-strength paper resins, chelating agents, ion exchange resins, oreprocessing aids, textile softeners, fuel additives, and corrosioninhibitors. Triethylenetetramine (TETA) has such major applications asepoxy curing agents, as well as the production of polyamides and oil andfuel additives.

It is recognized that linear polyalkylene polyamines (such as EDA, DETAand TETA) do not have the same industrial uses and demands as cyclicpolyalkyleneamines such as piperazine (PIP). As such, it can bedesirable to develop a process with sufficient selectivity in forming alinear polyalkylene polyamine to produce an amine composition with arelatively high ratio of a desired linear polyamine (e.g., DETA) to PIP.

One approach in producing linear ethyleneamines is reductive amination.Reductive amination (also known as reductive alkylation) involvesreacting an amine or ammonia with a carbon-containing material.Reductive amination involves the conversion of a carbonyl group(typically a ketone or an aldehyde) to an amine. A classic namedreaction is the Mignonac Reaction (1921) involving reaction of a ketonewith ammonia over a nickel catalyst, for example, in a synthesis ofalpha-phenylethylamine starting from acetophenone.

Reductive amination produces a variety of products, some of which havegreater economic value than others, depending upon current marketrequirements. For example, the reductive amination of monoethanolamine(MEA) produces lower molecular weight linear ethyleneamines, such asEDA, aminoethylethanolamine (AEEA), and DETA. A minor amount of higherlinear ethyleneamines, for example TETA and tetraethylenepentamine(TEPA) are also formed. In addition, cyclic ethyleneamines, such as PIP,hydroxyethylpiperazine (HEP), and aminoethylpiperazine (AEP) are alsoformed. Cyclic ethyleneamines tend to be less valuable than acyclicethyleneamines. Accordingly, for maximum economic benefits the catalystcompositions used in commercial reductive amination processes should beselective to the desired mixture of amine products, in addition to beinghighly active.

It is appreciated in reductive amination art that reductive aminationcatalysts must first be reduced before effecting the reaction, and thenhydrogen gas employed during the course of the reaction in order tomaintain catalytic activity and selectivity. During the reaction,reductive amination typically requires addition of ammonia.

One drawback relating to the catalysts and processes that have beendescribed for reductive amination to produce linear polyamines is thatthey do not typically provide high selectivity to DETA. In theseprocesses, as MEA conversions are increased to produce more DETA, PIPproduction becomes a significant problem. PIP can be formed from ringclosure of DETA or AEEA. Catalysts which are promoted with preciousmetals are known to show improved activity and selectivity for thereductive amination of MEA to EDA; however, high levels of DETA in theproduct mix result in concurrent high levels of PIP. As a result, thereis still a need for improved catalysts which give high EDA and DETAselectivities while minimizing the amount of PIP formed in the productmixture.

The reductive amination of lower aliphatic alkane derivatives, i.e.,diols such as ethylene glycol and alkanolamines such as MEA, is acommercially important family of processes. A variety of catalystcompositions for this purpose is found in the literature and is usedcommercially. Many of these catalyst compositions are based onnickel/rhenium mixtures (such as nickel/rhenium/boron catalystcompositions and the like) deposited on a support material.

As an alternative to reductive amination, linear polyamines can beprepared by transamination. Transamination is a transfer of an aminogroup from one chemical compound to another, or the transposition of anamino group within a chemical compound.

Many of the catalysts disclosed for transamination are high metal loadedcatalysts. Specifically, Raney nickel catalysts have been employed.These catalysts typically have small particle sizes, which makes theiruse in fixed bed processes difficult. To address difficulties with smallparticle sizes, more recent approaches have involved associating thecatalytic metals with a support. However, such supported catalysts havetypically included very large catalytic metal loading, and such highcatalytic metal loading can create its own drawbacks. For example, U.S.Pat. No. 7,053,247 (Lif et al.) describes particulate catalystscontaining 26 to 65% by weight of nickel on an oxide carrier. Catalystcompositions including such high levels of catalytic metals can bepyrophoric, more expensive, and do not appear to offer highselectivities for desirable transamination products (e.g., DETA).

Transamination reactions are typically performed at lower temperaturesthan reductive amination. A general problem in transamination processesof EDA to DETA and higher polyethylenepolyamines is the fact that atmoderate temperatures and pressures, these processes can result in toohigh a proportion of cyclic ethyleneamine compounds, such as PIP, whichrequires that the EDA conversion be kept low.

SUMMARY OF THE INVENTION

The invention provides catalyst compositions for the amination of targetreactants. In studies associated with the present invention, theinventive catalyst compositions have been shown to be advantageous forthe transamination of ethylenediamine (EDA) to diethylenetriamine(DETA). The catalyst compositions use a low metal loading and a catalystsupport that includes transitional alumina. The inclusion of these twofeatures in the catalyst composition provides remarkable activity andselectivity for transamination. The catalyst compositions are able toeliminate, or at least significantly reduce, the presence of a preciousmetal such as rhenium while maintaining a similar activity andselectivity to catalysts based on nickel/rhenium combinations. Theelimination of most or all precious metals from the catalyst compositionprovides an economic advantage, such as a lower catalyst cost. Further,the use of a supported catalyst at low metal loadings provide processingadvantages over small particle sized Raney nickel and other high metalloaded catalysts.

According to one aspect, the invention provides a catalyst compositioncomprising a support portion and a catalyst portion. The support portioncomprises an acidic mixed metal oxide comprising a transitional aluminaand a second metal oxide. In The catalyst portion is 25 wt. % or less ofthe catalyst composition and comprises one or more metals selected fromthe group consisting of cobalt, nickel, or copper. In the catalystcomposition there is no rhenium, or less than 0.01 wt. % rhenium.

In some aspects the transitional alumina comprises delta or theta phasealumina.

In another aspect, the catalyst composition of the invention is used inan amination process. The method includes a step of contacting thecatalyst composition of the invention to promote amination of a reactantto provide an aminated product. In some cases the amination process is atransamination process. In particular, the catalyst composition is usedin a method to promote the transamination of EDA to DETA.

Surprisingly, the catalyst composition of the invention showed similaractivity and selectivity to a nickel/rhenium catalyst for thetransamination of EDA to DETA. The catalyst composition of the inventionwas active at moderate temperatures and pressures, and provided goodselectivity to the desired product (DETA) while minimizing unwantedcyclic products, including piperazine and aminoethylpiperazine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of EDA conversion in the presence of different metalcatalysts at varying temperatures

FIG. 2 is a graph of EDA conversion in the presence of different metalcatalysts versus the presence of AEP in the reaction product containingDETA.

FIG. 3 is a graph of EDA conversion in the presence of different metalcatalysts versus the ratio of DETA to PIP in the reaction productmixture.

DETAILED DESCRIPTION

The embodiments of the present invention described below are notintended to be exhaustive or to limit the invention to the precise formsdisclosed in the following detailed description. Rather, the embodimentsare chosen and described so that others skilled in the art canappreciate and understand the principles and practices of the presentinvention.

All publications and patents mentioned herein are hereby incorporated byreference. The publications and patents disclosed herein are providedsolely for their disclosure. Nothing herein is to be construed as anadmission that the inventors are not entitled to antedate anypublication and/or patent, including any publication and/or patent citedherein.

In some aspects, the invention provides a catalyst composition fortransamination of amine-containing solutions, the catalyst compositioncomprising a support portion and a catalyst portion. According to theinventive aspects, the support portion can comprise an acidic mixedmetal oxide. The acidic mixed metal oxide can comprise a transitionalalumina and a second metal oxide. In some aspects of the invention, thetransitional alumina comprises at least 50 weight percent of the supportportion.

Transitional aluminas, or activated aluminas, are described in theEncyclopedia of Chemical Technology, Volume 2, 5th Edition, Kirk-Othmer(1992, page 221 et seq.) as a series of partially hydroxylated aluminumoxides (excluding alpha aluminas which are anhydrous in nature). Ingeneral, as a hydrous alumina precursor is heated, hydroxyl groups aredriven off, leaving a porous solid structure. As the activationtemperature increases through the transitional phases, the crystalstructures become more ordered, thus allowing for identification oftransitional aluminas by x-ray diffraction (hereafter “XRD”). Thesequences of transition are affected not only by the starting materials,but also by the coarseness of crystallinity, heating rates, andimpurities. The following transitions are generally accepted as thetransitions when the starting material is coarse gibbsite in air:

-   -   gibbsite→boehmite→gamma→delta→theta→alpha alumina.        Of the transitional aluminas described above, the delta and        theta phases can be particularly useful as a support portion of        a catalyst composition in accordance with the invention. Other        useful aluminas include mixtures of transitional aluminas and        aluminas such as gamma/theta, gamma/delta, delta/theta,        theta/alpha phases, or combinations thereof.

Transitional alumina carriers may be characterized using an X-raydiffractometer by methods known in the art. The following Table 1 liststhe accepted 2-theta values for the aluminas, as supplied by the JointCommittee on Powder Diffraction Standards International Center for X-RayDiffraction:

TABLE 1 Aluminas gamma 19.58 31.94 37.60 39.49 45.79 60.76 66.76 delta17.65 19.49 21.82 31.14 32.78 34.74 36.96 39.49 45.55 46.54 47.57 50.6760.03 61.35 62.26 64.18 66.76 67.31 73.33 75.37 theta 15.5 16.25 19.5431.509 32.778 34.939 36.743 38.871 39.911 44.856 46.4242 47.5849 50.680351.3931 52.6308 54.5575 56.7218 58.7033 61.2553 62.3387 64.0501 65.371467.4008 alpha 25.5 35.4 38.0 43.6 52.8 57.6 63.05 66.7 68.4

In some aspects of the invention, alumina can be employed in its hardestand most stable allotropic state, alpha-alumina (α-alumina) as acombination with a transitional alumina. In other embodiments, aluminacan be employed in its most amorphous state, gamma-alumina, incombination with a transitional alumina. However, in either of thesecases, the transitional forms of alumina are predominant in the aluminamixture.

As noted above, alpha alumina is not considered a transitional phase ofalumina. Rather, alpha alumina is the most thermodynamically stable formof alumina, and once formed, this phase is irreversible. Typically,then, alpha alumina is not present in a significant amount in thesupport portion of the inventive catalyst compositions. Although thecrystallinity of alpha alumina is highly distinctive when compared tothe transitional aluminas, in mixed phases that contain small amounts ofalpha alumina, the amount of alpha alumina present is not easilyquantified. However, due to the extremely low surface areas of alphaaluminas, useful mixed phases containing alpha alumina can be determinedby those which fall within the surface area ranges described herein.

Similarly, while gamma alumina is not considered a transitional phase ofalumina, it may also be present in the support portion. As with alphaalumina, gamma alumina is not typically present in a significant amountin the support portion. Useful mixed phases containing gamma alumina canbe determined by those which fall within the surface area rangesdescribed elsewhere herein.

Generally speaking, transitional aluminas are considered to beintermediate surface area supports. In accordance with the invention,support portions comprising transitional alumina can have surface areasin the range of about 10 m²/g to about 200 m²/g, or about 40 m²/g toabout 180 m²/g, or about 80 m²/g to about 180 m²/g.

As noted above, transitional aluminas can be obtained by heat-treatingtransitional alumina precursor materials such as gibbsite, boehmite, orbayerite to the desired phase transformation temperature. Processing caninvolve heat treatment of a transitional alumina precursor intotransitional alumina, in the form of delta or theta alumina, orcombinations thereof. Other techniques rely upon direct synthesis via awet chemical processing, such as through hydrolysis of aluminumalkoxide.

In another embodiment, transitional alumina material can be formedthrough a seeded processing pathway, such as that described inPCT/US2005/042048 (“Transitional Alumina Particulate Materials HavingControlled Morphology and Processing for Forming Same,” Bauer et al.)and U.S. Patent Publication No. 2008/0003131 A1 (“Transitional AluminaParticulate Materials Having Controlled Morphology and Processing forForming Same,” Bauer et al.). The transitional alumina can be present asa mass of particulate material, composed of particles that may be fullydispersed, partially agglomerated, or fully agglomerate. In the dryform, the particulate material may be in the form of a powder. Thisprocess typically includes providing a boehmite precursor and boehmiteseeds in a suspension, sol or slurry. The suspension, sol or slurry canbe heated treated (such as by hydrothermal treatment) to convert theboehmite precursor into boehmite particulate material formed ofparticles or crystallites. Heat treatment is then carried out to theboehmite particulate material to effect polymorphic transformation intotransitional alumina.

The transitional alumina precursor can be heat treated by calcination ata temperature sufficient to cause transformation into a transitionalphase alumina, or a combination of transitional phases. Typically,calcination or heat treatment can be carried out at a temperaturegreater than about 250° C., but lower than about 1100° C. Attemperatures less than 250° C., transformation into the lowesttemperature form of transitional alumina, gamma alumina, typically willnot take place. At temperatures greater than 1100° C., typically theprecursor will transform into the alpha phase. According to certainembodiments, calcination is carried out at a temperature greater than400° C., such as not less than about 450° C. The maximum calcinationtemperature may be less than about 1050° C. or 1100° C., these uppertemperatures usually resulting in a substantial proportion of thetaphase alumina, the highest temperature form of transitional alumina.

When it is desired to form a substantial content of delta alumina, thetransitional alumina precursor can be calcined at a temperature lowerthan about 950° C., such as within a range of about 750° C. to about950° C. In some embodiments, calcination can be performed attemperatures above about 750° C., or above about 775° C., or above about800° C., to avoid transformation into a predominant gamma phase alumina.

Calcination of the transitional alumina precursor can be carried out invarious environments including controlled gas and pressure environments.Because calcination is generally carried out to effect phase changes inthe precursor material and not chemical reaction, and since theresulting material is predominantly an oxide, specialized gaseous andpressure environments need not be implemented in most cases.

Typically, calcination can be carried out for a controlled time periodto effect repeatable and reliable transformation from batch to batch.Calcination times typically range from about 0.5 minutes to about 60minutes, typically about 1 minute to about 15 minutes.

Generally, as a result of calcination, the alumina material used to formthe support portion is predominantly (more than 50 weight percent)transitional alumina. The precise makeup of transitional alumina phasesmay vary according to different embodiments, such as a blend oftransitional phases. In some embodiments, a predominant amount of aparticular transitional phase can be present, such as at least about 50weight percent, or at least about 60 weight percent, or at least about70 weight percent, or at least about 80 weight percent, of a desiredtransitional phase. In further embodiments, the transitional alumina cancomprise essentially a single phase of transitional alumina (e.g., atleast 95 weight percent, or at least about 98 weight percent, or even upto about 100 weight percent of a single phase of transitional alumina).As discussed herein, the particular phase(s) of transitional alumina canbe determined by XRD.

Illustrative aluminas suitable for inclusion in the support portioninclude delta, theta, gamma/delta, gamma/theta, delta/theta, andtheta/alpha phases. In some embodiments, when alpha alumina is includedin the alumina support portion, it can be present in an amount that isabout 49 weight percent or less. In some embodiments, when gamma aluminais included in the alumina support portion, it can be present in anamount that is about 49 weight percent or less. In still furtherembodiments, the support can include one or more of the followingadditional alumina transitional phases: kappa, eta, rho, chi alumina,and combinations thereof.

In accordance with inventive aspects, the alumina is combined with asecond metal oxide to provide an acidic mixed metal oxide. Illustrativesecond metal oxides include oxides that, when combined with the alumina,can provide sufficient surface acidity to serve as a support portion forthe catalyst composition. Some binary metal oxides are known to havesurface acidity and have been used as solid acid catalysts, such assilica-alumina and alumina-boron oxide. Additional mixed metal oxidesthat may generate surface acidity can be determined using the hypothesisdescribed by Tanabe et al. (A New Hypothesis Regarding the SurfaceAcidity of Binary Metal Oxides, Bulletin of the Chemical Society ofJapan, 47(5):1064-1066 (1974)).

Useful second metal oxides comprise at least one element selected fromGroup IIA, IIIA, IVA, VA, VIA, IIB, IIIB, IVB, VB, VIB, VIIB and a rareearth element of the Periodic Table. Illustrative second metal oxides inaccordance with some embodiments include silicon, lanthanum, magnesium,zirconium, boron, titanium, niobium, tungsten and cerium. In someembodiments, the second metal oxide can comprise silicon.

In exemplary preparations, the support portion includes the second metaloxide in an amount in the range of about 5 weight percent to less than50 weight percent (based upon the weight of the support portion), ormore specifically in an amount in the range of about 5 weight percent toabout 35 weight percent.

Acidic mixed metal oxides can be prepared by one skilled in the art.Such known preparation methods include coprecipitation of metal salts,sol-gel techniques, ion exchange, mechanical mixing, and incipientwetness or precipitation on metal oxides.

The inclusion of an acidic mixed metal oxide comprising transitionalalumina in the support portion along with the low metal loading canprovide improved catalyst compositions. For example, catalystcompositions in accordance with the invention can include surprisinglylow (e.g., 20 weight percent or less) concentrations of catalyticmetals. Reduction in the amount of catalytic metals required to providethe desired activity and selectivity can provide significantly lowercatalyst costs. Surprisingly, the low-metal loaded catalyst compositionsof the invention demonstrate high activity and selectivity for thetransamination of EDA to DETA. The catalyst compositions do not requirethe presence of a precious metal for this activity and selectivity.Given this, the presence of a precious metal such as rhenium is able tobe eliminated or at least significantly reduced from the composition.The catalyst is active at moderate temperatures and pressures and canprovide good selectivity to the desired product (DETA) while minimizingcyclic products such as PIP and AEP.

The acidic mixed metal oxide support portion can be provided in anyconvenient morphology. The shape of the support will typically dependupon the shape required by the particular apparatus used to perform thetransamination reaction. Catalyst compositions can be made on supportsin the form of particles, powders, spheres, extrudates, pellets (cutextrudates), trilobes, quadrilobes, rings and pentarings. In someembodiments, particles can have an elongated morphology, which can bedescribed generally in terms of the particle's aspect ratio. The aspectratio is the ratio of the longest dimension to the next longestdimension perpendicular to the longest dimension. Alternatively,particles can have a platelet-shape, wherein the particles generallyhave opposite major surfaces, the opposite major surfaces beinggenerally planar and generally parallel to each other.

Morphology of the support portion can be further described in terms ofsupport portion size, more particularly, average support portion size.Average support portion size can be described as the average longest orlength dimension of the support material. Average support portion sizecan be determined by taking multiple representative samples andphysically measuring the support material sizes found in representativesamples. Such samples may be taken by various characterizationtechniques, such as by scanning electron microscopy (SEM). In someaspects, the support portion can be provided in the form of anextrudate. Extrudates ranging in diameter of about ⅛″ (3.175 mm) or lesscan be useful, for example in the range of about 1/32″ (0.79375 mm) toabout ⅛″. Another useful form of the support portion is a trilobe.Trilobes having a diameter of about ⅛″ or less can be useful, forexample in the range of about 1/16″ (1.5875 mm) to about ⅛″. Yet anotheruseful support form is a sphere, such as spheres having a diameter of 3mm or less.

In addition to the shape and average support material size, yet anotheruseful way to characterize morphology of the support portion is todescribe the specific surface area of the support portion. The acidicmetal oxide complex can be provided with a range of surface areas(m²/g), as measured by the commonly available BET technique. Accordingto embodiments herein, the support portion can have a relatively highspecific surface area, generally not less than about 10 m²/g, such asnot less than about 40 m²/g, or not less than about 80 m²/g, or not lessthan about 90 m²/g. Since specific surface area is a function ofparticle morphology as well as size, generally the specific surface areaof embodiments can be less than about 200 m²/g, such as less than about150 m²/g, or less than about 100 m²/g. In some embodiments, the surfacearea can be in the range of about 80 m²/g to about 180 m²/g.

Other useful characteristics of the support portion include pore volume(expressed as Hg intrusion values or N₂ values), and water absorption(expressed as a percentage of the dry sample weight). Illustrative porevolume (Hg pore symmetry) ranges are about 0.3 cm³/g to about 1 cm³/g.The percent water absorption is not narrowly critical since the catalystportion is less than 25 percent and can be easily incorporated usingincipient wetness techniques known to one skilled in the art. Anothercharacteristic of the support is the median pore diameter. Again themedian pore diameter is not narrowly critical over the surface area ofthe invention. Additionally, the pore size distribution may be unimodalor multimodal (e.g., bimodal, trimodal, etc).

Various methods can be carried out for depositing the one or more metalsof the catalyst portion on the catalyst support. In some modes ofpractice, the one or more metals of the catalyst portion are associatedwith the support portion by impregnation. Impregnation is particularlysuitable for this process, since lower metal loadings are used.

Although impregnation is one mode of preparing the catalytic support,other methods can be used to deposit the catalytic metal(s) on thesupport portion. For example, the metal(s) can be deposited on thesupport material by co-precipitation, sol-gel techniques, chemical vapordeposition, or ion exchange. These alternative methods are well known inthe art and can be used for the preparation of the catalyst support ifdesired. In order to describe the process of depositing the catalyticmetal(s) with the support, steps of an impregnation method will bedescribed.

As a general matter, the process of depositing the catalytic metal(s)can be performed to provide a support with a desired amount of the oneor more metals. As used herein, the total amount of the catalytic metalsin the compositions is referred to herein as the “catalyst portion,” andthe amount of the catalyst portion is expressed as a percentage byweight of the catalytic composition. According to the invention, thecatalyst portion has an amount of one or more metals of 25 wt. % or lessof the total weight of the catalyst composition. Lower amounts of thecatalyst portion can be used, such as about 20 wt. % or less of thetotal weight of the catalyst composition. A catalyst composition that is10 wt. % of the catalyst composition has 10 g of a catalyst metal, or acombination of catalyst metals, associated with 90 g of the support.

While the invention features that the catalyst portion has an amount ofone or more metals of 25 wt. %, lower amounts of the catalyst portioncan be used, such as about 20 wt. % or less of the total weight of thecatalyst composition. Generally, the catalyst portion includes enough ofthe one or more metals sufficient to provide a desired catalyticactivity when used in an amination process, such as transamination. Theinvention shows that lower amounts can be used which provide an economicadvantage while still providing desirable catalytic activity andselectivity. For example, in some modes of practice the amount of metalsin the catalyst portion is in the range of about 3 wt. % to about 18 wt.%, about 3 wt. % to about 13 wt. %, or about 5 wt. % to about 10 wt. %of the weight of the catalyst composition. Lower (below 3 wt. %) amountsof the catalyst portion may be used, although it is understood thatcatalytic activity at a given temperature may be decreased as well.Although lower catalytic activity may be acceptable in some catalyticmethods, most others would benefit from higher levels (i.e., above about3 wt. %).

The catalyst composition includes a catalyst portion wherein rhenium isnot present in the catalyst portion, or, alternatively, used only invery small amounts. For example, in many modes of practice the catalystcomposition is prepared without including rhenium when the catalystmetal(s) is deposited on the catalyst support. Any rhenium present inthe catalyst portion is desirably less than 0.01 wt. %, or less than0.005 wt. %. Other precious metals providing activity comparable torhenium can also be excluded from the catalyst portion. Examples ofother precious metals are rhodium, platinum, palladium, and iridium.Again, these types of precious metals can be excluded from the catalystcomposition altogether, or used in very small amounts. The eliminationof most or all precious metals from the catalyst composition provideseconomic advantages, including lower catalyst costs.

One exemplary catalyst composition includes a catalyst portion withcobalt in an amount of less than 25 wt. %, about 20 wt. % or less, inthe range of about 3 wt. % to about 13 wt. %, or in the range of about 5wt. % to about 10 wt. % of the catalyst composition. In one exemplarycatalyst composition, cobalt is present in an amount of about 7.0 wt %.

Another exemplary catalyst composition includes a catalyst portion withnickel in an amount of less than 25 wt. %, about 20 wt. % or less, inthe range of about 3 wt. % to about 18 wt. %, or in the range of about 5wt. % to about 15 wt. % of the catalyst composition. In one exemplarycatalyst composition, nickel is present in an amount of about 7.0 wt %.

Another exemplary catalyst composition includes a catalyst portion withcopper in an amount of less than 25 wt. %, about 20 wt. % or less, ofthe catalyst composition.

The catalyst portion can also include a mixture of two or more metals.In some aspects, the two or more metals are selected from the groupconsisting of cobalt, nickel, and copper. An exemplary combination ofmetals in the catalyst portion is a combination of cobalt and nickel.Another exemplary combination is a combination of cobalt, nickel, andcopper.

If the catalyst portion includes a mixture of two or more metals, themetals can be present in the catalyst portion in a predetermined weightratio. In some cases, the weight ratio of the two metals in the catalystportion is in the range of about 1:9 to about 9:1. In more specificcases, the weight ratio of the two metals in the catalyst portion is inthe range of about 1:4 to about 4:1.

As an example, the catalyst portion includes a combination of cobalt andnickel. In some aspects, one of the metals (cobalt or nickel) is presentin an amount in the range of about 1 wt. % to about 2.5 wt. %, and theother metal (cobalt if nickel is selected first, or nickel if cobalt isselected first), is present in an amount in the range of about 4.2 wt. %to about 6.0 wt. %. In other aspects, both of the metals (cobalt arenickel) are present in similar concentrations, for example both nickeland cobalt are present, individually, in an amount in the range of about2.5 wt. % to about 4.5 wt. %.

Exemplary catalyst portions include the following combination of metals:cobalt at about 1.7 wt. % and nickel about 5.1 wt. %; cobalt at about1.7 wt. % and nickel about 5.1 wt. %; cobalt at about 3.4 wt. % andnickel about 3.4 wt. %; and cobalt at about 1.13 wt. % and nickel about5.63 wt. %.

As another example, the catalyst portion includes a combination ofcobalt, nickel, and copper. In some aspects, the copper is present in anamount in the catalyst portion that is less than the cobalt or nickel.In other aspects, both of the metals (cobalt are nickel) are present insimilar concentrations, for example both nickel and cobalt areindividually present in an amount in the range of about 6.0 wt. % toabout 9.0 wt. %, and copper is present in an amount in the range ofabout 2.0 wt. % to about 5.0 wt. %. An exemplary catalyst portionincludes the following combination of metals: cobalt at about 7.4 wt. %,nickel about 7.4 wt. %, and copper at about 3.2 wt. %.

The selectivity of the catalyst composition may be further enhanced bythe use of metal promoter. The promoter may be a metal (or oxide) whichwhen incorporated into the catalyst composition further enhances theproductivity and/or selectivity in the amination reaction. Metals oroxides for use as promoters (optionally used in addition to the one ormore of cobalt, nickel, or copper present in the catalyst portion) arecompounds containing elements selected from Group IA, Group IIA, GroupIIIA, Group IVA, Group VA, Group VIA, Group VIIA, Group VIIIA, Group IB,Group IIB and Group IVB of the Periodic Table (IUPAC format). Examplesof metals include, but are not limited to, chromium, zinc, sodium,calcium, magnesium, manganese, molybdenum, strontium, lithium,potassium, barium, cesium, lanthanum, tungsten, iron, silver, titanium,niobium, aluminum, tin and mixtures of these metals.

Metal promoters can be added to the catalyst composition byco-impregnation or to the support either before or after incorporationof the one or more of cobalt, nickel, or copper salts. One or more metalpromoters can be added to the catalyst composition in a desiredamount(s). Typically, the metal promoters are present in an amount notgreater than the one or more of cobalt, nickel, or copper, in thecatalyst composition on a weight percent basis.

In some modes of practice the metal or metals of the catalytic portionare deposited on the support using an incipient wetness technique, oftenreferred to as incipient wetness impregnation (IW or IWI). In thistechnique an active metal precursor (or combination of active metalprecursors) is dissolved in an aqueous or organic solution. Themetal-containing solution (“impregnation solution”) is added to acatalyst support. Often, the impregnation solution is added in a volumethat is the same as the pore volume of the support. Capillary actiondraws the impregnation solution into the pores of the support. Theimpregnated support can then be dried and calcined to drive off thevolatile liquids of the impregnation solution. This process deposits thecatalytic metal or metals on the surface of the support portion.

In some modes of practice, an aqueous solution of a salt of the metal isprepared (the impregnation solution). If more than one metal is to beimmobilized on the support, the impregnation solution can include amixture of salts of the desired metals. Alternatively, if more than onemetal is to be immobilized on the support, more than one impregnationsolution can be prepared. The impregnation solution can be saturatedwith the one or more metal salts, or the one or more metal salts can beused in amounts less than saturation. The concentration of the one ormore metal salts in the impregnation solution can depend on factors suchas the desired amount of metal(s) to be deposited on the support, andthe solubility of the particular metal salt(s) used in the process.

Inorganic and/or organic salts can be used to prepare the impregnationsolution. Organic and inorganic salts of cobalt include, but are notlimited to, cobalt bromide, cobalt carbonate, cobalt chloride, cobaltfluoride, cobalt hydroxide, cobalt nitrate, cobalt nitrate hexahydrate,cobalt oxalate, cobalt perchlorate, cobalt phosphate, and cobaltsulfate. A cobalt-containing impregnation solution can be preparedcontaining one or more of these cobalt salts. In one mode of practicecobalt nitrate hexahydrate is used to prepare an impregnation solution.

Organic and inorganic salts of nickel include, but are not limited to,nickel nitrate hexahydrate, nickel formate, nickel acetate tetrahydrate,nickel acetate, nickel chloride, nickel carbonate and the like. Anickel-containing impregnation solution can be prepared containing oneor more of these nickel salts. In some modes of practice, nickel nitrateor nickel formate is used to prepare the impregnation solution.

Organic and inorganic salts of copper include, but are not limited to,copper gluconate, copper formate, copper chloride, copper bromide,copper fluoride, copper hydroxide, copper nitrate hydrate, coppersulfate pentahydrate, and copper pyrophosphate hydrate. In some modes ofpractice, copper nitrate hydrate is used to prepare the impregnationsolution.

In many modes of practice, the one or more metals to be deposited on thesupport are dissolved in a suitable solvent, such as deionized water,for preparation of the impregnation solution.

One or more impregnation solutions can be prepared to provide thetype(s) and total amount of metal(s) to be deposited on the supportportion. Since a lower amount of metal is associated with the support,the total amount of metal can be deposited in a limited number ofapplications. For example, the total amount of metal deposited can beapplied in one, two, three, or four applications. Although animpregnation solution can be prepared with a high concentration of metalsalt (i.e., a minimal amount of water), in some cases the total amountof the impregnation solution to be applied may be more than what thealumina support can hold by absorption. Therefore, in some modes ofpractice, the impregnation solution is applied to the support inmultiple steps, wherein a portion of the impregnation solution aboutequal to the absorption volume of the support is applied to the supportin one application step. Incorporation of additional metal(s) into thesupport may be further increased by techniques known to those skilled inthe art, such as increasing the time the support is in contact with thesolution.

The impregnation solution can be applied to the support using variousmethods. For example, the solution can be applied processes such as dripapplication, by immersion (e.g., dipping), or by spraying. Duringapplication, the support can be agitated by processes such as mixing,tumbling, stirring, or shaking. Mechanical equipment can be used tofacilitate agitation. Agitation during the application of theimpregnation solution can increase the uniformity of the impregnationsolution applied to the support.

After all or a portion of the impregnation solution is applied to thesupport, the support can be dried. In the drying step, the liquid whichsolvates the metal salt is volatized and removed from the support. Thedrying may be accomplished by any technique that sufficiently evaporatesthe volatile constituents of the impregnation solution. The drying stepcan comprise a calcination step, as further discussed herein. Multipledrying steps can be performed if the impregnation solution is applied inmore than one step. Therefore, an overall process for preparing thecatalyst composition can include multiple steps of disposing theapplication composition, and then drying the impregnated support. Thesteps of depositing and then drying can be performed until all of theimpregnation solution is used.

Typically, the impregnated support is dried at a temperature of above100° C. The elevated temperature can also be accompanied by a reducedpressure environment to accelerate removal of the liquid from thesupport. The support can be dried in air or in the presence of an inertgas, such as nitrogen. Drying is carried out for a period of timesufficient for removal of most or all of the liquid of the impregnationsolution. In some modes of practice, the step of drying is performed fora period of about one hour or more at elevated temperatures.

The process of preparing the catalytic composition can also involve oneor more steps of calcining the support. One or more steps of calciningthe support can be performed in the absence of the catalytic metals, andoptionally in the presence of the catalytic metals, or both.

In some modes of practice, given the high heat of calcination, dryingand removal of the liquid component of the impregnation solution occurs.Therefore, as used herein, calcination of the support meets therequirements of the drying step or steps, which are typically performedfollowing application of the impregnation solution. In addition,calcination can cause conversion of the metal salts into oxides. Thechoice of a particular calcination temperature can depend on thedecomposition temperature of the salts used.

Calcination normally takes place at temperatures below the melting pointof the materials used to form the support portion of the catalyticcomposition. For example, calcination is typically performed in therange of about 200° C. to about 1200° C., and more typically in therange of about 300° C. to about 500° C. A calcination step can take fora period of time in the range of a minute to hours (e.g., two or threeor more hours). Calcination can be carried out in the presence of air,or under inert gas. In one mode of practice, cobalt nitrate hexahydrateis deposited on the support portion. The impregnated support is thencalcined at a temperature of about 340° C.

In some modes of practice calcination is performed after one or moresteps of applying the impregnation solution. After all of theimpregnation solution has been applied the metal-loaded support can becalcined for a longer period of time to ensure substantial removal ofthe impregnation solution liquid. For example, in some specific modes ofpractice, the impregnation solution is applied to the support in two ormore steps, with calcination at about 340° C. for about one hour in airperformed after each step of applying, with a final calcination at about340° C. for about one hour in air.

Following metal impregnation and calcination, the catalyst compositioncan be reduced, converting the metal oxides produced in the calcinationstep to the reduced metal form. Typically, the metal-containing supportis reduced in the presence of hydrogen. The metal-containing support canbe contacted with hydrogen gas at a temperature that is about in thesame range as that used for calcination. The process of reduction can becarried out from about 30 minutes to about 24 hours, or more.

Following reduction, the catalyst composition can be stabilized withgentle oxidation. Typical stabilizing treatments involve contacting thereduced catalyst composition with oxygen or carbon dioxide. For example,in one mode of practice, the catalyst composition is treated with about1% O₂/N₂. Prior to using in an animation reaction, the catalystcomposition can be activated with hydrogen.

After impregnation and drying/calcination (with optional reduction) thecatalyst composition can optionally be stored or handled in an inertenvironment.

In some aspects, the invention relates to methods for making a catalystcomposition in a manner that reduces or minimizes mass transferresistance for the transamination of the amine-containing solution.Various techniques are known in the art to account for mass transferresistance in supported catalysts. Some illustrative methods foraddressing mass transfer resistance include: adjusting the morphology ofthe catalyst composition, selecting the form of the catalyst composition(e.g., by providing a thin coating of the active catalyst metals on thesurface of the support), and/or the selecting the size of the catalystparticles.

Accordingly, in some embodiments, the morphology of the catalystcomposition can be controlled to reduce or minimize mass transferresistance. For example, PCT Publication No. WO 2006/060206(“Transitional Alumina Particulate Materials Having ControlledMorphology and Processing for Forming Same,” Bauer et al.) describesalumina particulate material that contains particles comprisingtransitional alumina having an aspect ratio of not less than 3:1 and anaverage particle size of not less than about 110 nm and not greater than1000 nm. Various shaped particles are described, including needle-shapedparticles and platy-shaped particles.

In other embodiments, the catalyst portion is deposited on a poroussupport portion so that at least the active catalyst metals are providedin a very thin outer layer or “egg shell” structure, so as to minimizemass transfer resistance for the amine-containing solution. Thiscatalyst structure can also lower the active metal requirement for thecatalyst composition, and/or maximize contact of the active metals withthe amine-containing elements within the reaction solution.

Thus, in accordance with these embodiments, useful catalyst compositiondiameters can be in the range of about 0.8 mm to about 3.1 mm; surfacearea can be in the range of about 10 m²/g to about 200 m²/g;catalytically active metal concentration can be in the range of about 1weight percent to about 25 weight percent, and the catalyst portion canbe provided as a thin outer shell on the support portion.

Methods described in U.S. Pat. No. 5,851,948 can be utilized to create asimilar “egg shell” structure for the present inventive catalystcompositions. For example, the catalytic metals comprising the catalystportion (here, nickel and rhenium) can be added to the support portionas a thin outer layer or shell on the support portion. This smallthickness for the catalyst portion can be influenced by the flowcharacteristics of the nickel and rhenium salts and a suitable carrierliquid solution of an alcohol and water, the porosity and surface areaof the support portion, and the diffusion rate of the active metalliquid solution into the porous support portion. The flowcharacteristics of the nickel and rhenium in the alcohol-water carrierliquid having low surface tension is controlled so as to initially forma “cluster”-type structure of the nickel and rhenium in the carrierliquid on only the outer surface of the support portion. Such “cluster”type structures are formed because of valence differences between ionsof the active nickel and rhenium and molecules of the alcohol carrierliquid, and such larger “clusters” effectively impede penetration of theactive metal into smaller size pores of the support material. During thesubsequent drying, reducing and calcining steps for making the catalyst,the carrier liquid is destroyed and removed so that only the activemetals remain in uniformly dispersed sites in the thin outer “egg-shell”structure on the support portion. Suitable alcohol carrier liquids mayinclude ethanol, methanol and isopropanol.

This technique of depositing an active metal such as nickel and/orrhenium in a thin layer or shell on only the outer surface of thesupport portion advantageously provides a high localized concentrationof the active metals on the catalyst outer surface, where it is readilycontacted by the amine-containing compounds in the reaction solution.Techniques described in U.S. Pat. No. 5,851,948 (Chuang et al.,“Supported Catalyst and Process for Catalytic Oxidation of VolatileOrganic Compounds”) can be instructive in accordance with theseembodiments of the invention.

Catalytic metal can also be deposited on the surface of the supportportion according to techniques described by Komiyama et al.(“Concentration Profiles in Impregnation of Porous Catalysts: Nickel onAlumina,” J. of Catalysis 63, 35-52 (1980)). Utilizing the principlesdescribed by Komiyama et al., radial concentration profiles in thecatalyst compositions can be formed by impregnating the support portionwith aqueous catalytic metal (e.g., nickel) solutions. In accordancewith the present invention, a base can be used with nickel-formate toachieve surface deposition of nickel on alumina supports. Morespecifically, the pH effect on adsorption has been utilized to achievesurface impregnation of nickel by coimpregnating alumina supports withnickel formate (Ni(HCOO)₂.2H₂O) and aqueous ammonia. The result wassurface deposition of the nickel on the alumina supports. Theseprinciples can be further applied to catalyst compositions includingmore than one catalytic metal (e.g., more than one of cobalt, nickel,and/or copper).

In still further embodiments, internal mass transfer resistance can becontrolled by selecting a desirable particle size for the supportportion. As discussed in European Patent Application No. EP 1249440 A1(“Process for Preparing Linear Alkylbenzenes,” Wang et al.), both thecatalyst particle size and porosity can be adjusted to provide a desiredconversion and catalytic stability.

In use, the catalyst composition is added to promote an aminationreaction, such as a transamination process. The amount of catalystcomposition that is used to promote an amination reaction can bedetermined based on one or more of the following factors: the type andamount of reactants, the reactor (reaction vessel) configuration, thereaction conditions (such as temperature, time, flow rate, andpressure), the degree of conversion to a desired product(s), and theselectivity desired (i.e., the ratio of the desired product over anundesired product). The catalyst composition is present in the reactionzone in sufficient catalytic amount to enable the desired reaction tooccur.

The catalyst composition can be used for promoting a transaminationreaction, such as the transamination of a lower aliphatic alkanederivative. In one exemplary mode of practice, the catalyst compositionis used for promoting the transamination of ethylenediamine (EDA) todiethylenetriamine (DETA). The general reaction for the process is shownbelow:

The use of the catalyst composition will now be described with morespecificity for the transamination of EDA to DETA. EDA is a colorlessliquid with an ammonia-like odor and has molar mass of 60.103 g/mol, adensity of 0.899 g/cm³, a melting point of 9° C., a boiling point of116° C. EDA is miscible in water and soluble in most polar solvents.

The products found in the reaction mixture (i.e., the output of thereaction) include transaminated products, with diethylenetriamine (DETA)being the desired product in many modes of practice.Triethylenetetraamine (TETA) may be also be found, which results fromthe further reaction of DETA with EDA. Higher order polyamines formed ina similar manner may also be present in the reaction product mixture.Piperazine is also a transamination product, which is desirably presentin lower amounts in some modes of practice. Aminoethylpiperazine (AEP)is also formed in the reaction mixture. The reaction products may alsoinclude unreacted ethylenediamine, ammonia (which is eliminated in thetransamination reaction), and hydrogen.

The products in the reaction mixture are normally subjected to aseparation step. In the separation step hydrogen and ammonia (the lowmolecular weight compounds) are separated from unreacted ethylenediamineand the transamination products by fractional distillation. Hydrogen andethylenediamine are typically returned to the process.

Operating conditions can be chosen to provide a desired rate ofconversion, which has been shown to affect the selectivity for thedesired product. In particular, conditions are established to provide acertain rate of conversion of EDA, resulting in a desired selectivityfor DETA. For purposes of this invention, “EDA conversion” refers to thetotal weight percentage of reactant (e.g., EDA) lost as a result ofreactions. The conversion can vary depending upon factors such as thereactants, catalyst, process conditions, and the like. In manyembodiments, the conversion (e.g., of EDA) is at least about 10%, anddesirably less than about 50%, and in some modes of practice in therange of about 20% to about 40%. The temperature of reaction can beselected to provide a desired degree of conversion, which is discussedfurther herein. In some modes of practice the desired conversion of EDAis about 25% or more, such as in the range of from 25% to 65%.

For purposes of the invention, “selectivity” refers to the weightpercentage of converted reactant(s) that form a desired transaminatedproduct, such as DETA. In some modes of practice the percent selectivityto DETA is about greater than 50%, greater than 65%, such as in therange of about 65% to about 75%. Like conversion, selectivity will varybased upon factors including the conversion of the reactant(s), feedreactants, catalyst, process conditions, and the like.

The mixture of reaction products can also be defined in terms of theweight ratio of two products in the mixture. Typically, ratios usefulfor assessing the quality of the reaction mixture are of a desiredproduct to an undesired product (e.g., DETA/PiP), or desired product toa different desired product (DETA/TETA). For example, the mixture ofreaction products can be described in terms of the weight ratio of DETAto piperazine (DETA/PIP) at an EDA conversion of 25%. In some modes ofpractice, the catalyst composition of the invention is used in atransamination reaction to provide a DETA/PIP ratio of about 10:1 orgreater, about 10.5:1 or greater, about 11:1 or greater, about 11.5:1 orgreater, or about 12.0:1 or greater, such as in the range of about 10:1to about 13:1, about 10.5:1 to about 13:1, about 11:1 to about 13:1,about 11.5:1 to about 13:1, or about 12:1 to about 13:1.

The weight ratio of TETA to PIP may also be useful for determining theselectivity of the reaction. In some modes of practice, the catalystcomposition of the invention is used in a transamination reaction toprovide a TETA/PIP ratio at an EDA conversion of 25% of about 1:1 orgreater, about 1.1:1 or greater, about 1.2:1 or greater, about 1.3:1 orgreater, or about 1.4:1 or greater, such as in the range of about 1:1 toabout 1.5:1, about 1:2 to about 1.5:1, about 1:3 to about 1.5:1, orabout 1:4 to about 1.5:1.

Using the catalyst composition of the present invention, transaminationcan be performed using any suitable method and reaction equipment. Forexample, transamination can be carried out using a continuous process, asemi-continuous process, a batch-wise process, or a combination of theseprocesses. The transamination process using the catalyst composition ofthe present invention can be carried out in conventional high-pressureequipment with a heating feature. The equipment can have one or morefeatures which cause movement of the reactants and/or catalysts in theequipment, such as an agitator or pump. Various reactor designs can beused, such as a stirred-tank, fixed-bed, slurry, or fluid-bed reactors.The reactors can be designed for liquid-phase, gas-phase, multi-phase orsuper-critical conditions.

In some modes of practice, the reactant (e.g., EDA) is provided to thereaction bed that includes the catalyst composition as a stream, thestream having continuous flow. The reactant feed can be upflowing ordownflowing. Design features in the reactor that optimize plug flow canalso be used. Effluent from the reaction zone is also a streamcomprising the unreacted components of the feed stream (such as EDA) andthe reaction products (DETA). In some modes of practice, a liquid EDA isestablished in an upflow direction into the catalyst bed. In some modesof practice, a flow rate is established to provide a space velocity inthe range of about 5 gmol/hr/kg catalyst to about 50 gmol/hr/kgcatalyst, with an exemplary space velocity of about 15 gmol/hr/kgcatalyst.

The transamination reaction can be carried out with little or nohydrogen. However, as an optional component, hydrogen gas can be presentduring the transamination reaction. In some cases, hydrogen mayfacilitate the production of the reaction product, and inhibit or reducepoisoning of the catalyst. If desired, hydrogen can be included prior toand/or within the transamination reactor in an amount sufficient toaffect catalyst activity and product selectivity. Exemplary amounts ofhydrogen include 0.001 to 10.0 mole % based on liquid feed. A source ofhydrogen gas can optionally be combined with the ethyleneamines sourceand fed to the transamination reactor.

Optionally, ammonia can be used affect selectivity by inhibitingundesired reactions.

Generally, reaction temperatures for transamination process fall withinthe range of about 110° C. to about 180° C., and in desired modes ofpractice a reaction temperature in the range of about 130° C. to about160° C. is used. The temperature can be varied throughout the reactionprocess, and may fluctuate up to about 30%, or up to about 20% of thestarting temperature. The temperature of reaction can be selected toprovide a desired rate of conversion. In many modes of practice, thetemperature is chosen to provide a relatively low rate of conversion.

Typical reaction pressures range from about 200 psig to about 2000 psig,about 400 psig to about 1000 psig, and in some desired modes of practicethe pressure is about 600 psig.

The catalyst compositions of the present invention can be used in themethods described in any one of the Assignee's U.S. Patent Applications,listed and titled as follows:

U.S. Provisional Patent Application having Ser. No. 61/195,404 andentitled, “A PROCESS TO SELECTIVELY MANUFACTURE DIETHYLENETRIAMINE(DETA) AND OTHER DESIRABLE ETHYLENEAMINES VIA CONTINUOUS TRANSAMINATIONOF ETHYLENEDIAMINE (EDA), AND OTHER ETHYLENEAMINES OVER A HETEROGENEOUSCATALYST SYSTEM”, filed Oct. 6, 2008 in the name of Petraitis et al.,now U.S. Ser. No. 12/587,372 and published as U.S. 2010/0087683;

U.S. Provisional Patent Application having Ser. No. 61/195,405 andentitled, “METHODS FOR MAKING ETHANOLAMINE(S) AND ETHYLENEAMINE(S) FROMETHYLENE OXIDE AND AMMONIA, AND RELATED METHODS” filed Oct. 8, 2008 inthe name of Do et al., now U.S. Ser. No. 12/587,358 and published asU.S. 2010/0087684;

U.S. Provisional Patent Application having Ser. No. 61/195,412 andentitled, “METHODS OF MAKING CYCLIC, N-AMINO FUNCTIONAL TRIAMINES” filedOct. 6, 2008 in the name of Stephen W. King, now U.S. Ser. No.12/587,338 and published as U.S. 2010/0094007;

U.S. Provisional Patent Application having Ser. No. 61/195,454 andentitled, “METHOD OF MANUFACTURING ETHYLENEAMINES” filed Oct. 6, 2008 inthe name of Petraitis et al., now U.S. Ser. No. 12/587,350 and publishedas U.S. 2010/0087681;

Further, reagents and/or methods described in these co-pendingapplications can be incorporated by reference to further describe theuse of the catalyst composition of the present invention.

Aspects of this application are related to the following Assignee's U.S.Patent Application having Ser. No. 61/195,455, and titled “LOW METALCATALYST COMPOSITIONS INCLUDING ACIDIC MIXED METAL OXIDE AS SUPPORT”filed on Oct. 6, 2008 in the name of King et al., now U.S. Ser. No.12/587,351 and published as U.S. 2010/0087682.

The invention will now be described with reference to the followingnon-limiting Examples.

EXAMPLE 1 Catalyst Preparation

Unless otherwise noted, low concentration metal loaded catalystcompositions were prepared using the following generalized procedure.Table 2 includes a list of catalyst compositions that were prepared, andTable 3 includes a list of commercially available supported catalyststhat were used for comparative purposes.

Precursor salts of the metals (the nitrate salts of cobalt, nickel, andcopper, unless noted in Table 2) were dissolved in 70-80° C. water toform an impregnation solution. The final volume of the impregnationsolution was adjusted to equal the adsorption volume required for thenumber of times that the support was impregnated, and the quantities ofthe precursor salts were those calculated to give the metal compositionsprovided in the Examples. In each case the support was impregnated toincipient wetness by the addition of the appropriate amount ofimpregnation solution and gently agitated until all the liquid wasadsorbed. The sample was then placed in a muffle furnace and calcined inair for one hour at 340° C. or as otherwise specified in the Examples.When the support had cooled, additional impregnations were performeduntil all of the solution had been added. A calcination step at 340° C.was done after each impregnation.

For example, to prepare 6.8% cobalt on transitional (theta)alumina-silica support a cobalt solution was prepared by dissolving19.93 g cobalt nitrate hexahydrate into 74 mL deionized H₂O. Thesolution was added in two steps with an one hour calcination (in air) at340° C. between additions, and a 3 hour calcination after the finaladdition.

The transitional (theta) alumina-silica support was prepared having thecomposition Al₂O₃/SiO₂, 80:20 (wt), with a surface area of 150 m²/g, andPV of 0.880 cc/g, formed into ⅛″ extrudates. The catalyst was reduced at340° C. for 3 hours, and then stabilized using 1% O₂/N₂.

Catalyst Activation

Fifty (50) grams of the catalyst were charged to a 0.688 inch ID tubereactor, along with 50 cc fine glass beads (approx. 60 mesh). Thereactor was heated in a sandbath to 180° C. with hydrogen flowing at 30slph, and held at these conditions for 16 hours. Following activation,hydrogen flow was reduced to 3 slph, and temperature stabilized at 120°C. for one hour prior to starting liquid feed.

Liquid EDA (ethylenediamine) feed was established in an upflow directionto give a space velocity of 15 gmol/hr/kg catalyst. The mole ratio ofhydrogen to EDA was established at 0.18. The reactor was pressured to600 psig and lined out at 124° C. for 22 hrs. before collecting data.While maintaining the foregoing flow conditions, the temperature wasadjusted to cover a 20-40% range of conversion. The temperature wasvaried in a range from 124° C. to 146° C. A one hour timed sample wascollected at each temperature and analyzed by GC. The catalyst test wasrun for 487 hrs.

The cobalt catalyst was compared to a 6.8% nickel/1.8% rhenium (Example1-A) and a 6.8% nickel-only catalyst prepared on the same alumina-silicacarrier, and using like preparation techniques.

The catalyst compositions with low metal loading and not includingrhenium provided an increased weight ratio of low molecular weight,linear polyamines to higher molecular weight and/or cyclic polyamines inthe product stream. The low metal loaded catalyst compositions arehighly advantageous for converting EDA into DETA at high selectivitieswith relatively less PIP and higher polyamines in the product mix. Thelow metal loaded catalyst compositions of the invention also hadactivities, and selectivities to DETA, that were comparable to thenickel/rhenium catalysts. The catalysts of the present invention thatare shown in Table 2, which do not include rhenium, provide an economicadvantage over ones that include a precious metal.

In example 1-D, nickel formate was used, resulting in deposition of thenickel on the outside of the carrier, as a shell.

In example 1-H, the carrier was in the shape of a tri-lobe, whichminimizes diffusional effects.

The commercially available catalysts listed in Table 3 use variousmetals, at various loadings. However, these catalysts but do not use thetransitional alumina support material featured as featured in thecatalysts of the present invention, such as exemplified throughout Table2.

TABLE 2 Carrier Temp, ° C. SA for 25% % Sel DETA/ % AEP TETA/ DETA/Example Metals Carrier (m²/g) EDA conv. to DETA PIP in DETA PIP TETA ANi/Re (6.8/ alumina (theta)/silica 151 134 69.50 12.41 0.24 1.34 9.231.8 wt. %) (80:20) 1/16″ extrudate B Ni (6.8 wt. %) alumina(theta)/silica 107 144 68.14 11.07 0.57 1.28 8.66 (80:20) ⅛″ extrudate CNi (6.8 wt. %) alumina (theta)/silica 151 151 67.12 11.76 0.58 1.46 7.91(80:20) 1/16″ extrudate D Ni (6.8 wt. %)^(a) alumina (theta)/silica 107144 69.01 12.06 0.48 1.38 8.56 (80:20) ⅛″ extrudate E Ni (6.8 wt. %)^(a)alumina (theta)/silica 151 156 68.05 8.97 0.75 0.98 9.08 (80:20) 1/16″extrudate F Ni (13.0 wt. %) alumina (theta)/silica 151 142 68.52 12.280.34 1.40 8.77 (80:20) 1/16″ extrudate G Ni (13.0 wt. %)^(b) alumina(theta)/silica 151 142 68.74 12.51 0.32 1.42 8.87 (80:20) 1/16″extrudate H Ni (13.0 wt. %)^(c) alumina (delta/theta) silica 90 15167.43 11.48 0.71 1.36 8.26 (70:30) 1/16″ trilobe I Ni (20.0 wt. %)alumina (theta)/silica 107 155 60.14 5.13 1.95 0.53 9.36 (80:20) ⅛″extrudate J Ni (20.0 wt. %) alumina (theta)/silica 151 141 67.62 11.700.60 1.50 7.78 (80:20) 1/16″ extrudate K Ni/Co (3.4/ alumina(theta)/silica 151 138 69.49 12.25 0.30 1.32 9.27 3.4 wt. %) (80:20)1/16″ extrudate L Ni/Co (5.1/ alumina (theta)/silica 151 142 68.67 12.460.32 1.46 8.51 1.7 wt. %) (80:20) 1/16″ extrudate M Ni/Co (1.7/ alumina(theta)/silica 151 138 68.25 9.65 0.21 0.91 10.62 5.1 wt. %) (80:20)1/16″ extrudate N Ni/Co (5.67/ alumina (theta)/silica 151 143 68.6912.09 0.38 1.48 8.03 1.13 wt. %) (80:20) 1/16″ extrudate O Ni/Co (3.4/delta/theta mixed alumina 103 162 66.77 8.49 0.34 0.90 9.49 3.4 wt %)with 1.2% La2O3 1 mm sphere P Ni/Co/Cu (7.38/ alumina (theta)/silica 151140 69.38 12.90 0.28 1.29 9.99 7.38/3.24 wt. %) (80:20) 1/16″ extrudateQ Ni/Co/Cu (7.79/ gamma alumina 1/16″ 250 151 67.71 7.80 0.60 0.83 9.597.79/3.42 wt. %) extrudate SA = 250 R Co (6.8 wt. %) alumina(theta)/silica 107 131 69.21 9.67 0.22 0.89 10.79 (80:20) ⅛″ extrudate SCo (6.8 wt. %)^(d) alumina (theta)/silica 107 135 68.14 9.10 0.26 0.8910.18 (80:20) ⅛″ extrudate T Co (6.8 wt. %)^(d) alumina (theta)/silica151 142 70.99 11.85 0.20 1.07 11.03 (80:20) 1/16″ extrudate U Co (6.8wt. %) alumina (theta)/silica 151 139 69.01 11.75 0.17 1.11 10.35(80:20) 1/16″ extrudate V Co (6.8 wt. %) alumina (theta)/silica 107 13067.43 8.92 0.16 0.99 9.01 (80:20) ⅛″ extrudate W Co (6.8 wt. %)alumina(theta)/silica 150 139 68.54 9.48 0.17 0.97 9.75 (80:20) ⅛″extrudate X Co (6.8 wt. %) alumina(theta)/silica 170 138 68.29 8.89 0.240.88 10.09 (80:20) ⅛″ extrudate Y Co (6.8 wt. %) alumina(theta)/silica250 144 68.99 8.91 0.21 0.83 10.67 (80:20) ⅛″ extrudate Z Co (6.8 wt. %)theta alumina 1/16″ 127 159 67.58 7.92 0.27 0.79 9.99 extrudate AA Co(6.8 wt. %) gamma alumina 1/16″ 251 147 67.13 8.05 0.34 0.74 10.82extrudate BB Co (6.8 wt. %) silica/alumina (98:2) 68 143 65.32 8.09 0.750.91 8.77 1/16″ extrudate CC Co (6.8 wt. %) high purity silica 1/16″ 144144 65.68 6.79 0.67 0.62 10.82 extrudate DD Co (6.8 wt. %) high purityzirconia 98 171 47.94 2.26 2.84 0.25 8.92 ⅛″ extrudate EE Co (6.8 wt. %)titania 1/16″ extrudate 45 171 58.28 4.01 1.43 0.46 9.08 ^(a)made fromnickel formate ^(b)reduced at 440° C. ^(c)reduced at 400° C. ^(d)madefrom cobalt acetate

TABLE 3 Temp, ° C. or 25% % Sel DETA/ % AEP TETA/ DETA/ MetalsCommercial Catalysts EDA conv. to DETA PIP in DETA PIP TETA Example A Ni(50 wt. %) Sud-Chemie C46-8-03, 50% 147 67.03 9.40 0.60 1.11 8.42 Ni onalumina, 1/16″ trilobe B Ni (50 wt. %) Sud-Chemie C46-7-03, 50% 15662.89 7.12 1.89 1.03 6.91 Ni on silica-alumina (2:1), 1/16″ trilobe C Ni(50 wt. %) Sud-Chemie C46-8-03, ~50% 143 68.39 10.00 0.50 1.07 9.34 Nion alumina/silica clay 1/16″ trilobe D Ni (50 wt. %) Sud-ChemieC46-7-03, 50% 137 66.88 10.17 0.49 1.11 9.17 Ni on silica-alumina (2:1),1/16″ trilobe E Ni (60 wt. %) Engelhard Ni-3288-E, 144 67.22 7.93 0.601.03 7.97 alumina/Bentonite (silica)/Ca, 13/13/3 F Ni (57 wt. %)Engelhard Ni-0750-E, Ni on 144 63.82 5.92 0.93 0.63 9.43 gamma alumina,⅛″ extrudate G Ni (33 wt. %) Engelhard L6630-38A, 33% Ni on 150 66.4110.49 0.43 1.26 8.18 gamma alumina ⅛″ trilobe H Co (27 wt. %) EngelhardCo-0138-E, 27% 137 68.11 9.07 0.37 0.87 10.42 Co on Si—Al—Ca, 54/4/9,1/16″ trilobe I Co (14.5 wt. %) DeGussa 14.5% Co on 148 66.19 8.26 0.250.95 8.64 alumina (gamma), reduced (in H2O), 1 mm extrudate J Co (15 wt.%) Johnson-Matthey HTC Co 150 66.28 8.15 0.36 0.85 9.71 2000 RP 1.2 mmCo on alumina K Co/Zr (54/2 Sud-Chemie G-67, 54% Co/2% 138 61.17 5.160.62 0.71 7.39 wt. %) Zr on Kieselguhr, ⅛″ extrudate L DegussaMetalyst ™ alpha 166 60.93 6.02 1.94 0.90 6.69 1301-X019, ABMC (Raneytype), Ni—Al, 3 mm pellets M Degussa Metalyst ™ alpha 172 54.67 4.193.38 0.77 5.44 1301-X019, ABMC (Raney type), Ni—Al, 3 mm pellets NGrace-Davison Raney Ni 186 57.70 5.33 2.19 0.72 7.13 5886 fixed bed,Ni—Al (50% Ni), SA = 25, 8-12 mesh O Degussa Metalyst ™ beta 170 53.023.90 1.97 0.53 7.29 1350-X008, Raney type, Co—Al, 3 mm hollow sphereComparative Examples P Ni/Re (6.8/1.8 alumina (theta)/silica (80:20) 13469.50 12.41 0.24 1.34 9.23 wt. %) 1/16″ extrudate Q Co/Re (6.8/1.8)alumina (theta)/silica 80:20, 131 66.842 6.857 0.412 0.712 9.614 SA =107, ⅛″ extr R Co/Re (6.8/2.0) alumina (theta)/silica 80:20 148 67.4476.411 0.393 0.601 10.659 1/16″ extr

What is claimed is:
 1. A method for transaminating a reactant compoundcomprising a step of contacting a reactant compound with a catalystcomposition comprising: (a) a support portion comprising an acidic mixedmetal oxide comprising a transitional alumina comprising theta phasealumina, delta phase alumina, or mixtures of theta and delta phasealuminas and a second metal oxide, wherein the second metal oxide has aweight percentage that is less than the weight percentage of alumina,and (b) a catalyst portion comprising one or more metals selected fromthe group consisting of cobalt, nickel, and copper, wherein there is no,or less than 0.01 wt. % rhenium in the catalyst composition, and thecatalyst portion is 25 wt. % or less of the catalyst composition, andwherein the reactant compound becomes transaminated to an aminatedproduct.
 2. The method of claim 1, wherein the reactant compound isethylenediamine (EDA) and the aminated product is diethylenetriamine(DETA).
 3. The method of claim 2, wherein DETA is present in a productmixture containing PIP and the DETA to PIP ratio is in the range of 10:1to 13:1 at 25% EDA conversion.
 4. The method of claim 1, wherein thereactant compound is EDA and the aminated product istriethylenetetramine (TETA).
 5. The method of claim 4, wherein TETA ispresent in a product mixture containing PIP and the TETA to PIP ratio isin the range of 1:1 to about 1.5:1 at 25 EDA conversion.
 6. The methodof claim 1, wherein the reactant compound is EDA which is provided as aliquid feed to the catalyst composition, optionally in the presence ofhydrogen.
 7. The method of claim 1 wherein the catalyst portion is 20wt. % or less of the catalyst composition.
 8. The method of claim 7wherein the catalyst portion is in the range of 3 wt. % to 18 wt. % ofthe catalyst composition.
 9. The method of claim 8 wherein the catalystportion is in the range of 3 wt. % to 13 wt. % of the catalystcomposition.
 10. The method of claim 1 where the catalyst portioncomprises one or more metals selected from the group consisting ofcobalt and nickel.
 11. The method of claim 10 where the catalyst portioncomprises cobalt and nickel.
 12. The method of claim 11 wherein thecatalyst portion comprises cobalt and nickel in a weight ratio in therange of 1:9 to 9:1.
 13. The method of claim 10 wherein the cobalt ispresent in an amount in the range of 5 wt. % to 15 wt. %, or nickel ispresent in an amount in the range of 5 wt. % to 15 wt. %.
 14. The methodof claim 1 wherein the catalyst portion comprises no rhenium, or lessthan 0.005 wt. % rhenium.
 15. The method of claim 1 wherein thetransitional alumina comprises theta alumina.
 16. The method of claim 1wherein the support portion comprises at least 50 weight percenttransitional phase alumina.
 17. The method of claim 16 wherein thetransitional alumina is at least 80 weight percent of the aluminacontained in the support.
 18. The method of claim 1 wherein thetransitional alumina comprises a single phase of transitional alumina ofat least 95 weight percent of the alumina contained in the support. 19.The method of claim 1 wherein the second metal oxide is selected fromthe group consisting of silicon, lanthanum, magnesium, zirconium, boron,titanium, niobium, tungsten and cerium, and the second metal oxide ispresent in an amount in the range of 5 weight percent to less than 50weight percent, based upon the weight of the support portion.
 20. Themethod of claim 1 wherein the support portion is selected from the groupconsisting of an extrudate having a diameter of ⅛ inches (3.175 mm) orless; a sphere having a diameter of 3 mm or less; and a trilobe having adiameter of ⅛ inches (3.175 mm) or less.
 21. The method of claim 1wherein reactant compound is ethylenediamine (EDA) and the methodprovides an EDA conversion in the range of 10% to 50%.
 22. The method ofclaim 1 wherein reactant compound is ethylenediamine (EDA) and themethod provides an EDA conversion in the range of 25% to 65%.